# Simplest example:
#
#   use Rack::Get, '/ping_monitor' do
#     'pong'
#   end
#
# Rack::Response object is yielded as second argument to block:
#
#   use Rack::Get, '/json' do |env, response|
#     response['Content-Type'] = 'application/json'
#     %({"foo": "bar"})
#   end
#
# Example with regular expression -- match data object is yielded as third argument to block
# 
#   use Rack::Get, %r{^/(john|paul|george|ringo)} do |env, response, match|
#     "Hello, #{match[1]}"
#   end
#
# A false/nil return from block will not return a response; control will continue down the
# Rack stack:
#
#   use Rack::Get, '/api_key' do |env|
#     '12345' if env['myapp.user'].authorized?
#   end
module Rack
  class Get
    def initialize(app, path, &block)
      @app = app
      @path = path
      @block = block
    end

    def call(env)
      path = env['PATH_INFO'].to_s
      if env['REQUEST_METHOD'] == 'GET' && ((@path.is_a?(Regexp) && match = @path.match(path)) || @path == path)
        response = Rack::Response.new
        response.body = @block.call(env, response, match)
        response.body ? response.finish : @app.call(env)
      else
        @app.call(env)
      end
    end
  end
end